Multiple control towers?

In article ,
B A R R Y wrote:

On Fri, 16 Mar 2007 14:32:49 -0700, Hamish Reid
wrote:


My home field, Oakland (KOAK), is quite a bit smaller than DFW but it
has two completely separate towers...

Interesting...

Do you know why? Is there a terrain feature that prevents one tower
from seeing the whole field? Are the towers short?

Both towers are classic old 1960's things, and neither of them's
particularly short. And the airport's as flat as a pancake (and slightly
below sea level in many places).

It seems to be mostly history -- Oakland is basically two airports,
North Field and South Field, that are operationally and physically
linked, but have separate towers and quite separate concerns. North
Field (Runways 28R, 28L, 33, etc.) was there first (1920's), and
nowadays concentrates on GA and smaller freight; South Field (Runway
29/11) is the newer part built specifically for airlines and larger
freight operations in the 1960's, which seems to be when both towers
were built. Of course you occasionally see larger airline and freight
aircraft landing on North Field when necessary, and smaller GA aircraft
on South Field (especially for noise abatement reasons). After about
10pm, South Field tower takes over North Field operations as well. Yes,
there are some visibility issues, but nothing that would mandate two
separate towers as far as I can see (certainly South Field tower has few
problems handling me on North Field whenever I'm there late...).


Some very large Bravo airports here in the east only have one tower,
as the only folks who need to be in the cab are the controllers who
need to physically see the field. Everyone else (approach / departure
/ enroute, FSS, etc...) can be in the basement or even a different
building.

Oakland's departure and arrivals are handled by Northern California
(NorCal) Approach up in Sacramento. NorCal's precursor, Bay Approach,
used to be at Oakland on the North Field....

Hamish